To solve a Separate Result Unknown (SRU) problem, we modeled in three different ways: Modeling, Counting, and Derived Facts.

The problem we used for these examples is:



Connie had 13 marbles. She gave 5 to Juan. How many marbles does she have left?


MODELING has two types:



The first is called DIRECT MODELING:The second is just called MODELING:







COUNTING has three types:


COUNT FROM:
Beginning at 13, count backwards for a 5 count, and the number you end up with is your answer.
For example, 13 then 12 - 11 - 10 - 9 - 8 (5 count) and your answer is 8.
Number sentence: 13 - 5 = 8

COUNT UP TO:
Beginning at 5, count up to 13, and count the numbers you counted.
For example, 5 then 6 - 7 - 8 - 9 - 10 - 11 - 12 - 13, then counting from 6 to 13, you counted 8 numbers, so your answer is 8.
Number sentence: 5 + 8 = 13

COUNT DOWN TO:
Beginning at 13, count down to 8, and count the numbers you counted.
For example, 13, then 12 - 11 - 10 - 9 - 8, then counting from 12 to 8, you counted 5 numbers, so 5 is your answer.
Number Sentence: 13 - 8 = 5




FACTS


FACTS uses standard math facts to derive the answer.

13 - 5 = ?

5 = 3 + 2

13 - 3 -> 10, then 10 - 2 = 8

Number sentence: 13 - 5 = 8